Grain Boundary Migration
Grain boundary migration is the process by which grain boundaries in metals are moved by thermal activation. This reduces the total energy and promotes grain growth and recrystallization.
Physicochemical mechanism of action
Grain boundary migration refers to the thermal activation of grain boundaries in metals. This movement occurs to minimize the total energy of the system. Atomic diffusion and phase transitions are key processes here.
Metallurgical relevance & welding risks
Grain boundary migration is crucial for grain growth and recrystallization. If cooling is too fast, a fine, hard structure can result, which reduces toughness. If cooling is too slow, the grain enlarges and increases susceptibility to cracking.
Workshop practice & instructions
To effectively use grain boundary migration, controlled cooling is crucial. For high-carbon steel, the t8/5 time interval should be between 10 and 20 seconds. This ensures balanced grain growth and increases the toughness of the weld.